1) Field of the Invention
The present invention is directed to transducers.
2) Description of Prior Art
Transducers are devices that convert one form of energy into another form of energy. For example, a speaker converts electrical energy to sound or sound waves. The reverse would be the conversion of sound into electrical energy, which is known as a microphone. In addition to converting energy in a single direction, transducers can convert energy in two directions. For example, a single device could function as both a speaker and a microphone, or given transducer can be switched between operating in either a transmit mode and receive mode.
Generally, a transducer includes two types of components (active components and passive components). These components can be arranged as layers in the transducer. Active layers contribute to the energy conversion of the transducer. Passive layers compliment the active layers, but do not contribute to the energy conversion. For example, the passive layer can be a support for an active layer. Therefore, the materials and configuration of passive layers are chosen to have qualities that enhance the active layer performance. However, the desired qualities of the passive layer are different depending on whether the transducer is being used in transmit mode or receive mode. Consequently, current passive layers only compliment an active layer in a single mode of operation, (e.g., either transmit mode or receive mode).
Therefore, a transducer is desired that includes passive components or passive layers that compliment the active components of active layers of the transducer and therefore enhance the overall performance of the transducer in two modes of operation (e.g., transmit mode to receive mode).